Distortion

At around 0.5% the level of (barrel) distortion is relatively high for a standard lens
but still very low in absolute terms and nothing to worry about in the field.

The chart above has a real-world size of about 120x80cm.

Vignetting

Thanks to the sweet spot behavior on the D200 vignetting is very well controlled.
Wide-open vignetting is a little stronger at ~0.72EV which may be visible in
very critical scenes. From f/2 and up the problem is negligible.

MTF (resolution)

Standard lenses are simple optical designs that survived the tides of time without any
major updates during the last 25 years. Nonetheless they're as good as it gets at medium
aperture settings and the AF 50mm f/1.4 D performs in-line to these expectations.
At f/1.4 the center resolution is already very good whereas the borders are somewhat
soft. The contrast level is also quite low at this setting. This is quite typical for
high-speed standard lenses. At f/2 the borders are already significantly improved.
From f/2.8 to f/8 the resolution figures are excellent across the image field.

Below is a simplified summary of the formal findings. The chart shows line widths
per picture height (LW/PH) which can be taken as a measure for sharpness.
If you want to know more about the MTF50 figures you may check out the corresponding
Imatest Explanations

Chromatic Aberrations (CAs)

Chromatic aberrations (color shadows at harsh contrast transitions) are very low
at large aperture settings but increase a little when stopping down. However,
in the tested aperture range CAs never exceed 1px on the average at the image
borders so the problem isn't really significant.

Verdict

Similar to its cousin (AF 50mm f/1.8 D) the Nikkor AF 50mm f/1.4 D is a very good
performer. At f/1.4 the contrast is a little on the low side and the borders
may be a little soft but from f/2.8 & up the performance is really superb.
Distortions are detectable in the lab but not really significant enough to be
relevant in the real life. CAs are very low and vignetting is a non-issue except
at f/1.4 (on APS-C DSLRs). The build quality of the lens is very decent and the
AF performance leaves nothing to be desired.